Surgical cast cutters have been employed for many years. These tools are portable and have a small circular saw blade or cutter that oscillates through a limited angle, thereby assuring that the patient will not be injured while the cast is being removed. The oscillating cutter is driven by a suitable transmission, which may include a bifurcated fork, and the transmission is driven by an electric motor housed in the tool. The motor is usually an a.c. motor supplied by line voltage.
Because of the dust and debris generated by the cutter during removable of the plaster cast, the prior art (as exemplified by U.S. Pat. Nos. 3,103,069 and 3,481,036) has resorted to a built-in impeller or fan for generating a vacuum exhaust. The fan is driven directly by the rear end of the motor shaft and communicates with one end of a debris conduit or channel suitably formed in the housing to one side of the motor. The other end of the conduit terminates forwardly of the tool housing and adjacent to the cutter. As a result, the dust and debris are withdrawn from the vicinity of the cutter and are deposited laterally of the fan in a receptable carried by the tool.
Another prior art teaching of a surgical cast remover with a vacuum exhaust of the dust particles is U.S. Pat. No. 2,232,733, wherein the cutter is driven by a flexible power shaft, and wherein the vacuum hose is disposed substantially parallel to the flexible power shaft and terminates in a dust bag remote from the cutter. Moreover, in the general art relating to portable electric tools and appliances, it is well known to attach a vacuum hose to the housing of the tool for removal of the dust, debris or other particles generated during operation of the tool, and to connect the hose to a conventional vacuum cleaner located remotely from the tool; such an arrangement is exemplified by U.S. Pat. No. 2,929,177.
While these prior art designs and structural arrangements of surgical cast cutters and the like may be somewhat adequate for the purposes intended, nevertheless, there are a number of inherent disadvantages or deficiencies associated therewith, the more significant of which may be enumerated as follows: (1) the overall tool is relatively heavy and bulky, hence somewhat cumbersome, awkward and inconvenient to use; (2) the motor is operated from line voltage, which requires suitable insulation to maintain electrical safety requirements; (3) the a.c. motor is fairly large and runs at a relatively high speed, thereby increasing the ambient vibration levels, and as a result, any prolonged usage of the tool may become somewhat uncomfortable and tiring; (4) the motor-driven exhaust fan generates relatively high noise levels, which can become irritating in the usually serene atmosphere of a clinic or hospital. (5) the cost of original manufacture and assembly, as well as the cost of subsequent service and repair, are relatively expensive; and (6) the designs concentrate on a single-purpose tool, hence are relatively inflexible, and are not really adaptable to a broad line of related products for medical and other purposes.